Undercarriage for aircraft



Aug. 14, 1928. 1,680,511

A. H. G. FOKKER UNDERGARRIAGE FOR AIRCRAFT Filed Sept. 10, 1925 INVENTOR ATTORNEY Pate ted Aug. 14, 1928.

Amazon cmnn OFFICE.

IOZKEB, OI AMSTERDAM, NETHERLANDS, ASSIGNOR TO ATLANTIC AIBGBAI'I' CORPORATION, A CORPORATION OF NEW JERSEY.

I UNDERCARRIAGE FOB, AIRCRAFT.

original application fled Ily 85, 1888, Serial NO- 641324. Divided ber 10, 1925. Serial No. 55,444.

This invention relates generally to aircraft and is more especially directed to improvements in the landing gears or undercarriages of airplanes, as disclosed in my co-pending application for United States Letters Patent, filed May 25, 1923, Serial No. 641,324, of which the present application is a division.

As is well known, an airplane landing gear or undercarriage must be of a light and strong construction, and to efiiciently serve its urpose, should be capable of absorbing or issi atin the landing shocks, irrespective of t eir direction, so as to prevent transmission of the resultant detrimental forces to the fuselage and its components.

- that at the present Various types of undercarriages have been devised to attain the desired, end, but it has been found that while oneor another may respond to some of the requirements, it fails to meet others that are equally important, so

time there is no undercarriage structure which combines lightness and strength with a range of flexibility which enables it to efliciently function not only in absorbin the impact and rebound shocks, but in ta ing the side loads due to makin a landing while the airplane is drifting sidewise.

The primary object of this invention is to generally increase the eflicienc'y of airplane landing gears or undercarriages, by providing means for effectively overcoming the limitations which are inherent to structures of existing t es.

More speci cally, vention to provide a light strong undercarriage of a'simple and economical construction, which wlll efiectively take or absorb the impact and rebound landing shocks and the side loads which may develop from landing while the airplane is drifting sidewise or rolling, thereby preventing the trans: mittal of the resultant destructive forces to the airplane structure. It is also an object of my invention to provide an undercarrige having the aforesaid characteristics, in which the landing appendages are carried by an axle or member yieldably or floatably supported for uni-- versal movement in response to the loads imposed thereupon, under various conditions of landing.

' Other objects and advantages flowing from of an airplane,

it is an object of my inand this application filed Septemmy invention in its broadest aspect.

For the purposes of the present disclosure I have elected to illustrate and describe a preferred embodiment of my invention, it being manifest that changes in the "details and arrangement of parts of the structure, may be effected without departing from the spirit and scope of my invention as defined by the appended claims. i

In the accompanying drawings:

Figure 1 is a front elevation of a portion embodying an undercarriage made in accordance with my invention;

F lgure 2 is a longitudinal section on the lineal-a of Figure 1; F1gurc 3 is an enlarged view in elevation of a sectlon of the landing gear as seen in Figure 2, and I v Figure 4 is a view taken on the line b-b of Fi ure 3.

Referring now to the drawings in' detail, in which like characters of reference are employed to designate similar parts in the several views, 7 indicates the airplane fuselage and 8 the longrons thereof, to which the undercarriage or landing gear is attached as hereinafter described.

As will be observed, each of the main or supporting struts comprises two )refcrably tubular streamlined members 9 and converge u wardly to form an inverted V, the apex 0 which may be asuitable fitting within which the ends of the said members may be permanently fixed, as by welding.

Supported from the spaced lower ends of the members 9 and 10, to which it is integrally united or joined, as by welding, is a preferablv annular member or the present showing, are the wheels 14.

and in use,

10, whichring 11, which .may e formed of streamlined metal tubing,

Adjacent to each end of the axle 13, I provide a pair of spaced preferably annular collars or flanges 15 and 16, which may be discs apertured to fit upon thereto by welding.

Projecting laterally from each side of the ring or annular member 11, at diametrically opposite points thereon, are the stubs or arms 17 and 18, which may be of tubing, the respective ends thereof aving disc-like flanges or heads 17 and 18. These stubs or arms may be of any practical form and united to the ring or member 11 in any suitable manner.

The axle 13 is yieldably suspended within the ring or annular member 11, as aforesaid, by means of the rubber or elastic cord 19 which is looped or wrapped about the respective stubs or arms 17 and 18 and the axle 13, between the cooperatin retaining flanges 15, 16, 17 and 18 thereo as clearly shown in F 1%;1185 3 and 4. v

the formation of the loops in en agement with the stubs and axle respective y, it will be noted that the cord is crossed upon itself between the former and the latter, the intermediate or axle engaging loops 19 cooperating to provide a bearing which affords a strong and ample support for the axle, the tension of the cord serving to normally maintain the axle and the stubs in the same horizontal plane, with the axle concentric to the ring or annular member 11, as

aforesaid.

From the foregoing, it will be seen that I have provided an undercarriage or landing gear in which the axle is supported solely by the rubber or elastic cord. This floatable resilient mounting permits universal movement of the axle with relation to the ring or annular member the axle being bodily reciprocable radial y and longitudinally within the ring, under the yielding restraint of the cord, so that the im act and rebound shocks are completely absor ed or dissipated.

. Itis evident that, as the axle and ring are capable of relative movement, laterall of the airplane, the side loads resulting in the wheels or landing ap ndages striking the ound. while the airp ane is rollin or drifting sidewise when making a landing, will be taken by the elastic cord, the destructive side thrusts upon the wheels or the like, which frequently result in their collapse in present undercarriage structures, being rendered negligible.

The relative universal movement of the axle and ring'or annular member 11, as described, revents the transmission of detrimental fdrces to the airplane structure in landing, it being apparent that the tension of the rubber cord is taken by the stubs or arms 17 and 18, thereby relieving the struts of the attendant ben stresses. I

By employing inverte V struts, the members of which have a le point of iointure the axle for jointure with the underbody of the fuselage, the wei ht of the supported structure is equally istributed to the cooperating parts of the undercarriage. These bifurcated struts and the struts 12 which impart the necessary fore and aft rigidityl to the undercarriage, may be attached to t e fuselage by any suit able means, such, for instance, as the Wellknown ball and socket connection, employe in airplane construction, the structure be! ing laterally braced by the usual diagonal wires 20.

While I have described my invention with reference to the specific showing, it b comprehends an attain the objects hereinbefore set forth and in which the axle or landing appendage support is floatably mounted so as to be capable of universal movement with relation to a fixed member of the structure.

I claim:

1. An undercarriage for an airplane having a full floating axle capable of yielding in all directions to absorb anding, reboun and side load shocks.

2. An airplane undercarriage embodying supporting and bracing struts, a rigid member connecting said struts at their lowermost ends, windings of rubber cord stretched upon said member and an axle mounted within said windings which function as the sole support for said axle.

3. An airplane undercarriage embodying bifurcated supporting struts, a rigid connected thereto, an axle concentric wit said rin and means for connecting said axle an said ring for relative umversal movement.

4. An airplane undercarriage having members adapted for connection to the airplane, an axle and windings of rubber cord forming the sole connection between said axle and said members, whereby said axle is floatably suspended from said members for universal movement.

5. An airplane undercarriage comprising inverted V-shaped supporting struts, means for movably connecting the apex of each of said struts to an airplane fuselage, a rigid rin integrally united with the divergent en s of the strut members, centric with said ring and means for con' necting said axle to said ring, said means includm lateral projections on said rings, and ruber cord passed about said projw tions and said axle said axle thereby being floatably su ended within said rings.

6. An airp ane undercarriage embodying rigid supportin members adapted for connection to the airplane, capable of yielding in every direction fixed to said members and in engagement with said axle, said elements functioning as the sole support for said axle.

7. An airplane undercarriage having an ion yl undercarriage which wi I a rigid axle conan axle and elements I ily movement.

axle supported solely within loops. formed by rubber cord held in tension.

8. An airplane undercarriage embodying supportin struts, means for connecting the struts to t e fuselage of an airplane, a rigid member supported from said struts, an axle associated with said member and means of connection between said member and said axle adapted to ield in all directions, whereby said axle wifi be capable of relative bod- 9. An airplane undercarriage comprising members adapted for connection to the fuselage, an axle and resilient means connected to said axle and to said members, said means functioning as the sole support of said axle.

10. An airplane undercarriage embodying rigid supporting members adapted for con nectionto the alrpla-ne and an axle floatably suspended from said supporting members.

ANTHONY H. G. FOKKIER. 

